Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 29 Mar 2022 09:31:17 +0200 (CEST)
From:   Julia Lawall <julia.lawall@inria.fr>
To:     Marcelo Schmitt <marcelo.schmitt1@gmail.com>
cc:     corbet@lwn.net, mchehab+huawei@kernel.org, dlatypov@google.com,
        davidgow@google.com, linux-doc@vger.kernel.org,
        linux-sparse@vger.kernel.org, cocci@inria.fr,
        smatch@vger.kernel.org, linux-kernel@vger.kernel.org,
        skhan@linuxfoundation.org
Subject: Re: [cocci] [PATCH] Documentation: dev-tools: Add a section for
 static analysis tools
In-Reply-To: <YkImfPbNOzQBq5ZD@marsc.168.1.7>
Message-ID: <alpine.DEB.2.22.394.2203290930270.3490@hadrien>
References: <YkImfPbNOzQBq5ZD@marsc.168.1.7>
User-Agent: Alpine 2.22 (DEB 394 2020-01-19)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Precedence: bulk


On Mon, 28 Mar 2022, Marcelo Schmitt wrote:

> Complement the Kernel Testing Guide documentation page by adding a
> section about static analysis tools.
>
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
> ---
> Hey everyone,
>
> I think this patch can be a good addition to the documentation as
> discussed in the thread for the testing guide documentation page:
> Link: https://lore.kernel.org/linux-doc/CABVgOS=2iYtqTVdxwH=mcFpcSuLP4cpJ4s6PKP4Gc-SH6jidgQ@mail.gmail.com/
>
> If you think it would be worth it, I can try making something more
> elaborated. Maybe provide some guidance on when to use each tool.
> I've been studying how Linux device drivers are tested.
> Here's a post I wrote talking about some testing tools.
> Link: https://marcelosc.gitlab.io/how-is-linux-tested/
>
> Best regards,
> Marcelo
>
>  Documentation/dev-tools/testing-overview.rst | 29 ++++++++++++++++++++
>  1 file changed, 29 insertions(+)
>
> diff --git a/Documentation/dev-tools/testing-overview.rst b/Documentation/dev-tools/testing-overview.rst
> index 65feb81edb14..b00511109a9d 100644
> --- a/Documentation/dev-tools/testing-overview.rst
> +++ b/Documentation/dev-tools/testing-overview.rst
> @@ -115,3 +115,32 @@ that none of these errors are occurring during the test.
>  Some of these tools integrate with KUnit or kselftest and will
>  automatically fail tests if an issue is detected.
>
> +Static Analysis Tools
> +======================
> +
> +In addition to testing a running kernel, one may also scout for bugs by
> +analyzing the source code semantics. Three tools are well known for serving this
> +purpose.
> +
> +Sparse can help test the kernel by performing type-checking, lock checking,
> +value range checking, in addition to reporting various errors and warnings while
> +examining the code. See the Documentation/dev-tools/sparse.rst documentation
> +page for details on how to use it.
> +
> +Smatch extends Sparse and provides additional checks for programming logic
> +mistakes such as missing breaks in switch statements, unused return values on
> +error checking, forgetting to set an error code in the return of an error path,
> +etc. Smatch also has tests against more serious issues such as integer
> +overflows, null pointer dereferences, and memory leaks. See the project page at
> +http://smatch.sourceforge.net/.
> +
> +We also have Coccinelle as an option within static analyzers. Coccinelle is
> +often used to aid collateral evolution of source code, but it can also help to
> +avoid certain bugs that have been expressed semantically. The types of tests

"avoid certain bugs that have been expressed semantically" would be better
as something like "avoid certain bugs that occur in common patterns"

julia


> +available include API tests, tests for correct usage of kernel iterators, checks
> +for the soundness of free operations, analysis of locking behavior, and further
> +tests known to help keep consistent kernel usage. See the
> +Documentation/dev-tools/coccinelle.rst documentation page for details.
> +
> +These static analysis tools support running tests on the whole source tree or
> +over a specific file or directory.
> --
> 2.35.1
>
>